The present invention pertains to digital communication switching systems and more particularly to a small remotely located digital time division multiplexing switching system.
With the advent of population growth from large metropolitan areas, there is an increased requirement for digital switching systems. Population density in these outlying areas are not as great as the metropolitan areas. As a result, use of large digital switching systems is areas of lesser population density would be uneconomical. However, small digital switching systems can be provided to serve these areas and to interface with these larger digital switching systems.
These smaller digital switching systems are typically located remote from the larger switching systems and provide for handling between a few hundred and a few thousand telephone subscribers.
Large switching systems could be used to serve this need, however, they would be uneconomical and inefficient because much of their capacity would be unused. One such switching system is a non-folded T-S-T modular network taught by U.S. Pat. No. 3,956,593, issued to A. A. Collins et al., on May 11, 1976. Another large time-space-time switching network is taught in U.S. Pat. No. 4,005,272, issued on Jan. 25, 1977, to A. A. Collins et al. Both of the above mentioned switching systems are large and would, therefore, be uneconomical in small remote unit applications.
Another large switching system is taught by U.S. Pat. Nos. 4,406,005; 4,399,369; 4,339,533; 4,399,534; 4,392,223; and 4,402,077, all issued to N. Simmons et al., during 1983 and assigned to the same assignee as the present invention. These patents depict the switching network of the base unit of the GTD-5 EAX system. Again, this is a large switching system which would be uneconomical in a remote unit application.
Accordingly, it is the object of the present invention to provide an efficient and economical remotely located digital time division multiplexing switching system, providing for a subscriber capability of between a few hundred and a few thousand telephone subscribers.